1. Field
The following description relates to a power amplifier.
2. Description of Related Art
In accordance with a rapid increase in demand for a high data communication rate in a wireless transmitting and receiving system, a multi-carrier scheme or a complicated digital modulation scheme has been adopted. Thus, a power amplifier included in a transmitting and receiving module performing wideband code division multiple access (WCDMA) or long term evolution (LTE) communications has been required to have high linearity to be suitable for these approaches.
For example, in a case in which modulation schemes such as quadrature amplitude modulation (QAM) that is in a higher modulation scheme than a binary phase shift keying (BPSK) modulation scheme are used, linearity of the power amplifier may be further deteriorated.
However, because there is generally a trade-off between the linearity of the power amplifier and the power efficiency of the power amplifier, a power amplifier having a high linearity may have a negative influence on the power efficiency. For example, in order to improve the linearity of the power amplifier, a bias voltage of a gate terminal of a field effect transistor (FET) included in the power amplifier may be adjusted, which may have a large influence on the power efficiency of the power amplifier. In addition, controlling the linearity by managing the bias voltage of the gate terminal is sensitive to a change in process-voltage-temperature (PVT).